With the wide application of the Internet, people can get lots of information from the web. However, due to the rapid growth of the web contents, it becomes more and more difficult for web users to find required information rapidly and accurately. Currently, web users mainly rely on search engines to find required information. Generally, the process in which a web user uses a search engine to find required information is as follows: the web user submits a query, which may be, for instance, a single keyword or a combination of keywords, to the search engine. Then, the search engine produces a ranked list of the search results based on the submitted query. The ranked list is returned and displayed on the browser used by the web user. The web user obtains the part of the search results of interest to him through viewing segments of the returned ranked list of the search results.
However, such a method of using a search engine to find information commonly has a problem that the search engine always returns too many search results. In this situation, since the screen size of a computer display is limited, it is impossible to display all the search results simultaneously to the web user. Thus, the web user usually needs to browse many Web pages to find the required information, resulting in low efficiency of the web user getting information. On the other hand, according to an investigation of web users, in most cases, a web user only looks at the first few web pages of the ranked list of search results. Thus, in fact, the search quality of a web user searching information is also very low.
In order to improve search quality, some methods for improving the browsability of search results have been proposed in recent years. Vivisimo Company proposed a solution in which the search results returned by a search engine are clustered and the clustering results are visually displayed together with the ranked list of the search results. Although this solution may provide a convenient way for web users to know the clustering of the search results, it only displays the clustering results and the ranked list of search results simultaneously but independently, without presenting their correlations clearly and visually to the web users. Besides, the solution only clusters and displays part of the search results (for instance, the first 210 search results); if the web user selects a clustering item in the clustering results, the search results contained in the clustering item will be displayed, but no more relevant search results can be produced, so the web user cannot get more information of interest.